Hiroya Oku(奥 浩哉,Oku Hiroya?, born September 16, 1967 in Fukuoka, Fukuoka) is a manga artist who is the creator of Gantz, Zero One and HEN, all of which have been serialized in Young Jump. He is finished working on his most renowned manga, Gantz, which began in July 2000. His manga often contain explicit violence and gore, as well as sexual situations.

He won the second prize of the Youth Manga Awards in 1988, under the penname Yahiro Kuon.

There are two series of Hen; the first, with kanji, ran for 13 volumes—the first three are short story collections, and the remaining ten are a romantic comedy in which both leads are male. The short stories were later repackaged as "Aka" and "Kuro".

The second series, 8 volumes, with the title only in romaji, is a romantic comedy in which both leads are women. This series has been adapted into an anime.

Zero One (1999–2000)

There are only three volumes, about a video game tournament. It was not successful, and ended abruptly.

It consists of 37 volumes. The first eight have been adapted into the first 21 episodes of the two seasons of the anime, with the final five episodes consisting of a different story that doesn't follow the manga.